Field of the Invention
An embodiment relates to a control method for power saving in which a memory can transition from a first power state to a second power state that consumes lower power than the first power state, in accordance with a control signal.
Description of the Related Art
There is a memory that can transition to a low power consumption mode, and return from the low power consumption mode in accordance with a control signal (Japanese Patent Application Laid-Open No. 2007-164822). The memory includes an input node that receives a control signal called a resume-standby (RS) signal (hereinafter, referred to as an RS signal), and transitions to a resume state and to a standby state in accordance with the RS signal.
In Japanese Patent Application Laid-Open No. 2007-164822, a plurality of memories is connected in a daisy chain, and a delay circuit is provided between two memories so that the control signal input to a memory module is delayed on a subsequent stage. Thus, inrush current can be prevented from being generated when the plurality of memory modules returns from the low power consumption mode.
In multifunction peripherals (MFPs) having a plurality of functional modules for a printing function, a scanning function, and the like, power control is preferably performed for each functional module so that power consumption of unused functional modules is reduced. More specifically, a configuration that can perform the power control for each functional module has, for example, the advantage that when the printing function is used, the scanning function is not used, and thus the power consumption can be reduced in the functional module that performs the scanning function.
When a plurality of functional modules is operated in conjunction, they need to concurrently return from a power saving state. For example, when the copy function is performed, both a print image processing module used for performing the printing function and a scan image processing module used for performing the scanning function need to return from the power saving state.
When the plurality of functional modules each independently regulates the control signal input to the memory, memory modules of one or more functional modules might recover from the low power consumption mode at the same timing. Thus, the inrush current is generated when the plurality of functional modules returns from the power saving state.